Crash via unchecked backspace buffer traversal
Published Jul 14, 2023 · Updated Feb 13, 2025
Out-of-bounds read in w3m 0.5.3+git20230121 allows local users to crash the browser by opening a crafted HTML file. In checkType, each backspace moves the plens pointer to the preceding multibyte-character length without checking the start of plens_buffer, so excess backspaces drive the pointer out of bounds and corrupt the length later consumed by growbuf_to_Str. A user must open or dump the malicious file; the demonstrated result is a process abort, not data disclosure or code execution.
Summary
What happened
Out-of-bounds read in w3m 0.5.3+git20230121 allows local users to crash the browser by opening a crafted HTML file. In checkType, each backspace moves the plens pointer to the preceding multibyte-character length without checking the start of plens_buffer, so excess backspaces drive the pointer out of bounds and corrupt the length later consumed by growbuf_to_Str. A user must open or dump the malicious file; the demonstrated result is a process abort, not data disclosure or code execution.
The record
- CVE
- CVE-2023-38253
- Published
- Jul 14, 2023
- Updated
- Feb 13, 2025
- Vendor
- Tatsuya Kinoshita
- Product
- w3m
- Classifications
- CWE-125
- Attack vector
- local
- Privileges
- unauthenticated
Timeline
How it unfolded
- Jul 14, 2023CVE publishedPublication date reported by the CVE source.
- Feb 13, 2025Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
Affected versions are unavailable in this record. Check the vendor advisory for version and patch details.
What conditions does exploitation require?
What is affected?
Published CVSS scores
CVSS describes severity. EPSS estimates exploitation probability.
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Weakness, pattern, technique
Public exploit references
- poc2 crafted HTML inputproof of concept · demonstrated
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Technologies
Your stack
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Your stack
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